It is called in this way the sediment which is attracted to the bottom of a fermentation tank after that wine has fermented, or, in the case of a sparkling wine, the sediment that remains in the bottle after the second fermentation until disgorgement. Lees usually consist of dead cells of yeast used during fermentation, but may also contain grapes, skins, pulp and stalks. The fermented wine is then decanted into another container and the lees are removed from the tank. The wines that remain on the lees for a longer period of time (a method called "sur lie") tend to develop a richer and a more complex character.